.box {
  width: 100%;
  height: 200px;
  overflow: hidden;
  ul {
    list-style: none;
    li {
      float: left;
      margin-right: 10px;
      &:nth-child(2) {  
        color: blue;
      }
      p {
        line-height: 1.5em;
        #aa {
          color: aqua;
          font-style: italic;
        }
        a {
          text-decoration: none;
          color: #123456;
          position: relative;
          &:hover {
            text-decoration: underline;
            color: red;
          }
          &::before {
            content: "";
            display: block;
            width: 100%;
            height: 1px;
            position: absolute;
            left: 0;
            top: 0;
            border-top: 1px solid #000;
          }
        }
      }
    }
  }
}
